ABSTRACT
Intravenous injection of 1 microg/kg desmopressin to rabbits not only accelerated clotting of arterial blood (maximally by 59.16 +/- 8.53% after 1 h), but also increased the number of microvesicles containing the integral enzyme 5'-nucleotidase in the arterial blood from the initial level of 36.26 +/- 8.08 ncat/liter to a maximum of 99.65 +/- 15.8 ncat/liter after 15 min.
Subject(s)
Deamino Arginine Vasopressin/pharmacology , Hemostasis/drug effects , 5'-Nucleotidase/blood , Animals , Blood Coagulation/drug effects , Factor VIII/metabolism , Hemostasis/physiology , Rabbits , Tissue Plasminogen Activator/blood , Weibel-Palade Bodies/drug effects , Weibel-Palade Bodies/metabolism , von Willebrand Factor/metabolismABSTRACT
The dynamics of microvesicle formation in arterial blood in generalized Schwartzman phenomenon was studied. Successive (with 24-h interval) intravenous injections of endotoxin to rabbits in a dose of 1 mg/kg and 3 mg/kg caused an increase in the content of microvesicles in the blood, some of them containing ecto-5'-nucleotidase. Biphasic changes in arterial blood clotting time and erythrocyte hemolysis were observed.
Subject(s)
Endotoxemia/pathology , Membrane Microdomains/metabolism , 5'-Nucleotidase/blood , Animals , Endotoxins , Lipopolysaccharides , Male , Membrane Microdomains/drug effects , Rabbits , Shwartzman PhenomenonABSTRACT
We studied binding of (125)I-labeled prothrombin to platelets in the presence of circulating endogenous lupus anticoagulant. Lupus anticoagulant modulated the interaction and increased affinity of prothrombin for calcium-independent binding sites on platelets. The number of these sites decreased, while the total number of calcium-dependent binding sites increased. Our results indicate that lupus anticoagulant plays a role in the binding of prothrombin to nonactivated platelets.
Subject(s)
Blood Platelets/metabolism , Lupus Coagulation Inhibitor/metabolism , Prothrombin/metabolism , Binding Sites , Calcium/metabolism , Humans , Iodine Radioisotopes/metabolism , Protein Binding , Prothrombin/chemistryABSTRACT
In the rabbit vessels of a. mesenterica, total lysis of fibrin occurred within 60-90 minutes whereas in the renovascular basin the process took 30 minutes longer. This seems to be due to synthesis of a plasminogen activator.
Subject(s)
Fibrinolysis/physiology , Mesenteric Arteries/physiology , Renal Artery/physiology , Animals , Female , Fibrinogen/pharmacokinetics , Fibrinogen/radiation effects , Fibrinolysis/radiation effects , Fluorescein-5-isothiocyanate , Fluorescent Dyes , Male , Mesenteric Arteries/radiation effects , Rabbits , Renal Artery/radiation effects , Thrombin/pharmacokinetics , Thrombin/radiation effects , Time Factors , Ultraviolet RaysABSTRACT
Tissue thromboplastin injected i.v. in the form of microsomal fraction of the aorta intima was rapidly eliminated from the blood flow but did not enter into the lymph in any considerable amount. The disintegration products of the microsomal fraction of the aorta intima are released into the blood flow mostly within 5 days as revealed by the 5'-nucleotidase activity.
Subject(s)
Thromboplastin/metabolism , Animals , Aorta/ultrastructure , Cell Membrane Permeability , Ear/blood supply , Female , Humans , Injections, Intravenous , Lymph/metabolism , Lymphatic System/ultrastructure , Male , Microsomes , Rabbits , Thromboplastin/administration & dosage , Time Factors , Veins/ultrastructureABSTRACT
The authors studied in the bloodflow the appearance of the damaged external cellular membranes of the heart during the development of experimental myocardial infarction. The appearance of the external cellular membranes was judged by the activity of their specific marked 51-nucleotidase. It was established that myocardial infarction leads to increased activity of 51-nucleotidase in the blood plasma, which is retained for about 1 month. The maximum of activity of 51-nucleotidase reflects the most intensive resorption of the damaged cardiac tissue, and is seen from 3 to 7 days after the accident. During these time limits thrombotic complications are especially dangerous.
Subject(s)
Myocardial Infarction/enzymology , Nucleotidases/blood , Alkaline Phosphatase/blood , Animals , Dogs , Enzyme Activation , Female , Male , Thrombosis/enzymology , Time FactorsABSTRACT
Experiments on 67 rabbits were performed to examine the injured external cell membranes of the vascular wall, appearing in the blood flow in the course of the development of alimentary hypercholesterolemia. The time of the appearance in the blood plasma of the external cell membranes was judged from the activity of their specific marker, 5'-nucleotidase. An abrupt increase in 5'-nucleotidase activity was disclosed in the blood plasma at the height of hypercholesterolemia. The latter circumstance served as an objective criterion for injury to ther external cell membranes and might be regarded as a risk factor in thrombus formation.
Subject(s)
Blood Vessels/pathology , Hypercholesterolemia/pathology , Thromboplastin/blood , 5'-Nucleotidase , Alkaline Phosphatase/blood , Animals , Cell Membrane , Cholesterol/blood , Cobamides/therapeutic use , Female , Hypercholesterolemia/drug therapy , Male , Nucleotidases/blood , Phospholipids/blood , Rabbits , Vitamin B 12/therapeutic useABSTRACT
The work is devoted to the analysis of hemocoagulation and fibrinolytic properties of a commercial preparation of alkaline phosphatase from the mucosa of the small intestine of a chick. The results of this work indicated that the catalytic separation of the phosphate groups under the effect of alkaline phosphatase was not a significant link in the biochemical mechanism of the blood plasma coagulation and activation of the fibrinolytic process.
